Vatican City - The Vatican Wednesday said an ultra- conservative bishop needs "clearly and publicly" to distance himself from remarks he made denying the Holocaust, before he can "assume functions" within the Roman Catholic Church.

The Vatican in a statement also said Pope Benedict XVI was not aware of Richard Williamson's stance on the Holocaust when the pontiff last month revoked a 1988 excommunication order against him and three other bishops of the renegade Society of Saint Pius X (SSPX).

The Vatican statement came in the wake of an uproar, especially in the pontiff's native Germany, over last month's decision to re-admit the British-born Williamson into the church.

On Tuesday German Chancellor Angela Merkel had called on Benedict to speak out bluntly on Williamson's denial that the Nazis killed 5 million to 6 million European Jews during the Second World War.

If a decision of the Vatican gave rise to the impression that it was permissible to deny the Holocaust, and raised fundamental questions about the relationship with Judaism, this could not be left to stand without further action, she said.

The Vatican's chief spokesman Father Federico Lombardi subsequently rebutted the criticism, saying Benedict, in a January 28 general audience - three days after the revocation of the excommunication orders were announced - had left no room for doubt about "his condemning of Holocaust-denial claims."

Wednesday's statement, issued by the Holy Sees Secretariat of State, said it was specifying details regarding the position of the pardoned clerics, the SSPX and the Holocaust-denial remarks made by Williamson.

Benedict had revoked the excommunication "to reach out in a benign manner" to requests made by one of the bishops, the SSPX Superior General, Bernard Fellay, for a rapprochement with Rome.

"His Holiness wanted to remove an obstacle that prejudiced opening a door of dialogue. He (Benedict) now expects the four Bishops to show an equal amount of goodwill through their total adherence to Church discipline and doctrine," the statement said.

Until such time, the lifting of the excommunication order "does not change the legal situation" of SSPX which at the moment together with the four bishops "has no legal function within the Church," it added.

In the interview recorded in Germany in November 2008, Williamson alleged the scale of deaths of Jews under the Nazis was no more than "200,000 to 300,000."

The interview was aired on Swedish television on January 21 on the same day that the pontiff signed a decree revoking the excommunication orders. The decision was announced by the Vatican three days later.

Fellay has since distanced the SSPX from the Holocaust-denial remarks while Williamson, who is based in Argentina, described them as "imprudent" in a letter in which he apologized to the pontiff.

The incident has drawn criticism from Jewish religious leaders and Israeli official, as well as Catholic clerics who have questioned the Vatican's handling of the case.

But the strongest reaction has been in Germany which continues to wrestle with the legacy of war crimes.

German prosecutors are studying whether to charge Williamson with Holocaust denial, which is a criminal offence in Germany and which is common among far rightists. (dpa)